Sealing station and method for its operation

ABSTRACT

A sealing station for a packaging machine for sealing a foil on to a packaging tray is provided. The sealing station comprises a sealing tool whereby the sealing tool is configured to apply a sealing force for sealing on to the foil and the packaging tray. The sealing tool includes an upper tray holding fixture and a lower tray holding fixture that are arranged at different heights, whereby each is configured for holding at least one packaging tray.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Application Number 102011110407.4 filed Aug. 12, 2011 to Bernd Jokele entitled “Sealing Station and Method for its Operation,” currently pending, the entire disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a sealing station for packaging and a method for operating a sealing station.

BACKGROUND OF THE INVENTION

A packaging machine with a sealing station, for example, from DE 102 37 933 A1, is known in the art. The sealing station comprises a sealing tool that seals a cover film onto a packaging tray by means of pressure. Normally, a plurality of packaging trays are arranged next to one another horizontally and in a plurality of rows. The pressure applied for the sealing thereby drops as the number of horizontally arranged packaging trays increases, because the sealing force is distributed across a greater surface area. Detrimental in this is that the quality of the sealing seam is reduced as the sealing pressure drops.

A further packaging machine, which however is configured as a chamber machine for vacuum packaging and not for sealing packaging trays with the help of a sealing force or a sealing pressure, is described in US 2005/0178090 A1. In this, a plurality of individual vacuum chambers are arranged one above the other and configured for the purpose of packaging objects under pressure independently of one another. Detrimental in this is that this arrangement cannot seal any packaging trays.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a packaging machine sealing station that, with the simplest design means possible, allows the sealing of the greatest possible number of packaging trays.

The inventive sealing station for a packaging machine of the present invention is configured for sealing a foil on to a packaging tray by means of a sealing tool. The sealing tool applies a sealing force for sealing to the foil and the packaging tray and is characterised by the fact that the sealing tool comprises an upper and a lower tray holding fixture that are arranged at different heights, whereby each is configured for holding at least one packaging tray. In one embodiment, the development of the sealing tool allows a number of packaging trays to be arranged at different heights or one above the other. In this way, it is possible to hold a number of packaging trays in the sealing tool that is the same as the number in the case of the horizontal arrangement of packaging trays without the sealing pressure dropping. It is rather the case that, due to an arrangement of the packaging trays such that they lie one above the other, it is possible to reduce the effective surface of the sealing force and, as a result, to increase the sealing pressure. This brings about greater quality in the sealing seam. The sealing tool also makes it possible, however, for the capacity of the sealing tool to be virtually doubled or generally multiplied while keeping the sealing force constant as compared to the horizontal arrangement of the packaging trays.

In order to maximize the capacity of the sealing station per work cycle, the sealing tool can be configured for applying the sealing force simultaneously on to a packaging tray held in the upper tray holding fixture and on to a packaging tray held in the lower tray holding fixture. As a result, the sealing can be carried out simultaneously with a plurality of packaging trays.

In one embodiment of the invention, the sealing tool comprises an upper sealing plate and a lower sealing plate. This arrangement allows a simple and effective application of the sealing force to the sealing tool or to the packaging tray.

For a parallelization of operational steps within the sealing station, the upper tray holding fixture and the lower sealing plate may be movable in a coupled manner. In this way it is possible to achieve, for example, closing the upper tray holding fixture while at the same time opening the lower tray holding fixture.

For an application of the sealing force adapted to the respective situation, it can be advantageous if a device for registering the sealing force and for regulating the sealing force to a specific value is provided. It is consequently possible to apply an individual sealing pressure depending on the condition of the foil or of the packaging tray. It is also possible to regulate the sealing force depending on the temperature in the sealing tool.

For the packaging of perishable foodstuffs, the sealing tool may be configured to evacuate the packaging tray.

One embodiment of the invention provides for the upper and the lower tray holding fixtures to be movable by means of a lifting unit. This allows a height adjustment of the tray holding fixture and provides spatial flexibility.

For the effective loading of the upper and lower tray holding fixtures, a gripper system can be provided for the sealing station. The gripper system ideally makes it possible for the upper and the lower tray holding fixtures each to be loaded independently of the other.

The invention also relates to a packaging machine with a sealing station of the aforementioned type. This packaging machine is configured so that the sealing force necessary for the sealing can be applied to the lower and upper tray holding fixtures simultaneously, thereby enabling a plurality of packaging trays to be sealed simultaneously in levels arranged one above the other.

The invention also relates to a method for operating a sealing station of the aforementioned type. The method is characterised in that a sealing force can be applied simultaneously to at least one packaging tray located in an upper tray holding fixture and at least one packaging tray located in a lower tray holding fixture. This enables a plurality of packaging trays to be sealed simultaneously by means of a sealing tool in a sealing station. Consequently, packaging trays that otherwise would be arranged horizontally in a plurality of tracks can be arranged one above the other, so that by reducing the sealing surface while keeping the sealing force constant, a greater sealing pressure results within the sealing tool. It is also possible to increase the holding capacity of the sealing tool with respect to the same number of packaging trays arranged horizontally by doubling the tray holding fixtures and simultaneously retaining the sealing pressure.

The sealing tool can be fed packaging trays in a second level, after a first level of the sealing tool has received packaging trays. This makes it possible to parallelize a plurality of work cycles.

In one embodiment of the method, it is possible to evacuate the first and the second level of the sealing tool individually. The evacuating can consequently be carried out in operational steps that are independent of one another.

Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.

DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the accompanying drawing, which forms a part of the specification and is to be read in conjunction therewith in which like reference numerals are used to indicate like or similar parts in the various views:

FIG. 1 is a side view schematic detail of a packaging machine with a sealing station in accordance with one embodiment of the present invention;

FIG. 2 is a side view schematic detail of a packaging machine with a sealing station in a partially opened state in accordance with one embodiment of the present invention;

FIG. 3 is a side view schematic detail of a packaging machine with a sealing station in another partially opened state in accordance with one embodiment of the present invention;

FIG. 4 is a side view schematic detail of a packaging machine with a sealing station during the sealing in accordance with one embodiment of the present invention; and

FIG. 5 is a side view schematic detail of a packaging machine seen in the transport direction in accordance with one embodiment of the present invention.

Components that are the same in the figures are given the same reference numbers throughout.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purposes of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures.

The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled.

FIG. 1 shows a schematic detail of a packaging machine 1. This is a tray sealing machine (tray sealer) that is used to package objects into prefabricated trays.

The shown detail of the packaging machine 1 has a sealing station 2 according to the invention. The sealing station 2 is arranged on a machine frame 3 that comprises a lifting unit 4. A sealing tool 5 is mounted movably on the lifting unit 4. The lifting unit 4 is configured to move the sealing tool 5 in a direction that is perpendicular to the machine frame 3.

The packaging machine 1 comprises a transport level 6 in which a feed device 7 and a removal device 8 for transporting packaging trays 9 are arranged. The feed device 7 and the removal device 8 can each be belt conveyor systems. The feed device 7 is provided to feed unsealed packaging trays 9 to the sealing station 2, while the removal device 8 is provided to transport sealed packaging trays 9 away.

The sealing station 2 additionally may have on one side of the sealing tool 5 an unwinding device 10 a, executed as a roll, for a foil 11, which in this embodiment is a foil web that can be unwound. The unwinding device 10 a is configured to feed the foil 11 to the sealing tool 5 in a controllable manner. A winding device 10 b can be provided on the opposite side of the sealing tool in order to act in combination with the unwinding device 10 a in order to wind up the foil 11.

FIG. 5 shows a detail of the packaging machine 1 in the transport direction. As depicted in this figure, a further unwinding device 10 c is provided that acts in combination with a winding device 10 d in order to unwind or wind up a further web-shaped foil 11 a. The unwinding device 10 c and the winding device 10 d are arranged on the left and on the right side, respectively, of the sealing tool 5, as seen in the transport direction. This means that the unwinding devices 10 a and 10 c are arranged on the sealing station 2 such that they are offset from each other by 90°. It is thereby possible that the two foils 11, 11 a executed as webs can be fed to the sealing tool 5 simultaneously and independently of each other.

As shown in FIG. 1, the sealing tool 5 additionally comprises a lower tray holding fixture 12, which acts in combination with a lower sealing plate 13 in order to apply a sealing force on to the packaging tray 9 and the foil 11. The unwinding device 10 a and the winding device 10 b can be coupled to the lower sealing plate 13. Above the lower sealing plate 13, the sealing tool 5 has an upper tray holding fixture 14, which can be coupled to the lower sealing plate 13. The upper tray holding fixture 14 acts in combination with an upper sealing plate 15. The lower sealing plate 13 is integrated into the sealing tool 5 in such a way that it can be detached from the lower tray holding fixture 12. The upper tray holding fixture 14 and the lower sealing plate 13 can be coupled to the upper sealing plate 15. The lower tray holding fixture 12 and the upper tray holding fixture 14 can each hold a plurality of packaging trays 9. In on embodiment, the lower tray holding fixture 12 and the upper tray holding fixture 14 can each hold three packaging trays 9 in a row. The lower tray holding fixture 12 and the lower sealing plate 13 form an assembly within the sealing tool 5, as do the upper tray holding fixture 14 and the upper sealing plate 15, whereby each assembly can be configured to evacuate the packaging trays 9 and/or to treat the packaging trays 9 with gas.

Above the sealing tool 5, the sealing station 2 has a controllable force device 16, which in one embodiment is an inflatable membrane. The upper sealing plate 15 is coupled to the force device 16, for example, by means of a bolting that functions as a guide. The force device 16 is provided for the purpose of generating the sealing force that is to be applied to the sealing tool 5 in order to seal the packaging tray 9. For this purpose, the lower tray holding fixture 12 and the lower sealing plate 13, as one assembly, and the upper tray holding fixture 14 and the upper sealing plate 15, as another assembly, are each constructed in such a way that they each transfer the sealing force on to the packaging tray 9 arranged between the tray holding fixtures 12, 14 and the sealing plates 13, 15 and on to the foil 11 arranged in an overlapping manner on the packaging tray 9.

For the control of the force device 16 and for the lifting unit 4, a controller 17 may be provided that is connected to the force device 16 by means of an electric line 17 a. The controller 17 may act in combination with a sensor system 17 b, that registers, for example, the current sealing force and/or the temperature of the sealing tool 5. The data provided by the sensor system 17 b are processed by the controller 17. In order to inflate the force device 16 in a controlled manner, the sealing station 2 additionally may include a compressor 18, which is configured to work in combination with the controller 17.

In order to load and unload the lower tray holding fixture 12 and the upper tray holding fixture 14, a gripper system 19 may be provided. The gripper system 19 is configured for the purpose of simultaneously receiving one or more packaging trays 9 from the feed device 7 and transporting it or them into the lower tray holding fixture 12 and/or the upper tray holding fixture 14. The gripper system 19 can additionally remove packaging trays 9 from the sealing tool 5 and pass them to the removal device 8 for further transport. In order to support the gripper system 19, the feed device 7 and the removal device 8 can each be adjusted in the height.

The operation of the sealing station 2 according to the invention is explained in the following on the basis of several examples.

The packaging machine 1 and the sealing station 2 integrated therein work in cycles.

Starting with the starting state of the sealing station 2 as shown in FIG. 1, first as many packaging trays 9 are provided via the feed device 7 as can be held by the sealing tool 5. In one embodiment, the sealing tool 5 can hold three packaging trays 9 two times, namely three packaging trays 9 in the lower tray holding fixture 12 and an additional three packaging trays in the upper tray holding fixture 14.

FIG. 2 shows a schematic detail of the packaging machine 1 with the sealing station 2 in a partially opened state. The upper tray holding fixture 14 is decoupled from the upper sealing plate 15 and lowered by means of the lifting unit 4. The now freely accessible upper tray holding fixture 14 is fed a set of packaging trays 9, in this example, three pieces, by means of the gripper system 19. Likewise, the foil 11 can be introduced into the interspace between the upper tray holding fixture 14 and the upper sealing plate 15 with the help of the unwinding device 10 a and wound on the opposite side by the winding device 10 b. The foil 11 here can be introduced into the sealing tool 5 either as a continuous foil web or instead as individual foil pieces.

In FIG. 3, the packaging machine 1 is depicted as a schematic detail with the sealing station 2 in an additional, partially opened state. After, as previously described, the upper tray holding fixture 14 has been filled with packaging trays 9, the upper tray holding fixture 14 is now moved towards the upper sealing plate 15 and coupled to this so that the upper tray holding fixture 14 and the upper sealing plate 15 form a closed unit. Together with the upper tray holding fixture 14, the lower sealing plate 13 is now moved in a coupled manner. As a result, there results a free area between the lower tray holding fixture 12 and the lower sealing plate 13, so that the lower tray holding fixture 12 can take in a further set of packaging trays 9. The lower tray holding fixture 12 can be filled with the packaging trays 9 by means of the gripper system 19. The unwinding device 10 c feeds the foil 11 a to the free area between the lower tray holding fixture 12 and the lower sealing plate 13. On the opposite side, the foil 11 a is wound up by the winding device 10 d.

Simultaneously with the loading of the lower tray holding fixture 12 or after the closing of the upper tray holding fixture 14, the packaging trays 9 that are arranged in the upper tray holding fixture 14 can be evacuated.

After the filling of the lower tray holding fixture 12, the sealing tool 5 is closed by means of the lifting unit 4 moving the lower tray holding fixture 12 upwards in the direction of the lower sealing plate 13. The lower tray holding fixture 12 and the lower sealing plate 13 are coupled to each other. Following this, the packaging trays 9 of the lower tray holding fixture 12 can be evacuated.

FIG. 4 depicts a detail of the packaging machine 1 with the sealing station 2 according to the invention during the sealing. After both the upper tray holding fixture 14 and the lower tray holding fixture 12 have each been equipped with a set of the packaging trays 9 and fed the foil 11 and the packaging trays 9 have been evacuated, the sealing tool 5 is now, with the help of the lifting unit 4, raised in the direction of the controllable force device 16. The force device 16, which, as described above, can involve a controllable and inflatable membrane, now applies the sealing force adjusted depending on parameters, such as the temperature in the sealing tool 5 or the condition of the packaging tray 9 and foil 11, for example, on to the upper sealing plate 15. The sealing force is transmitted by way of the upper tray holding fixture 14 on to the lower sealing plate 13 coupled thereto, so that both sets of packaging trays 9 are sealed simultaneously with the two sets of foils 11.

After the sealing, the connection between the upper tray holding fixture 14 and the upper sealing plate 15 is disconnected and, by lowering the lifting unit 4, the sealing tool 5 is opened, so that the packaging trays 9 sealed with the foil 11 can be removed, by means of the gripper system 19, from the upper tray holding fixture 14. The sealed packaging trays 9 are either fed with the help of the removal device 8 to a next work station (not shown) of the packaging machine 1 or taken away as a finished product from the packaging machine 1.

A new set of packaging trays 9, which is provided by means of the feed device 7, is introduced into the tray holding fixture 14 by way of the gripper system 19. An additional set of the foil 11 is likewise introduced between the upper tray holding fixture 14 and the upper sealing plate 15 by way of the unwinding device 10 a. Following this, the sealing tool 5 is again closed, by means of the lifting unit 4 again moving in the direction of the force device 16. The lower tray holding fixture 12 is decoupled from the lower sealing plate 13, so that the lifting unit 4 moves downwards alone with the lower tray holding fixture 12. The sealing tool 5 consequently opens between the lower tray holding fixture 12 and the lower sealing plate 13, so that the set of packaging trays 9 sealed with the foil 11 can be removed from the lower tray holding fixture 12 with the help of the gripper system 19. The sealed packaging trays 9 are further transported or transported away by means of the removal device 8.

Departing from the depicted embodiments, the packaging machine 1 and the sealing station 2 according to the invention can be modified in many ways. For example, the lower and upper tray holding fixtures 12, 14 can each be configured to receive a plurality of tracks of packaging trays simultaneously, so that, for example, three tracks of packaging trays can be arranged two times in each of the tray holding fixtures 12, 14. It is consequently possible that a plurality of packaging trays 9 can be sealed per work cycle.

It would additionally be conceivable that in addition to tray holding fixtures 12, 14, further tray holding fixtures are provided that are appropriately arranged one above the other. The holding capacity of the sealing station 2 can therefore be additionally increased.

From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting.

The constructions and methods described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow. 

1. A sealing station for a packaging machine, adapted for sealing a foil on to a packaging tray, the sealing station comprising: a sealing tool including an upper tray holding fixture and lower tray holding fixture arranged at different heights and each being configured to hold at least one packaging tray; wherein the sealing tool is configured to apply a sealing force on to the foil and the packaging tray.
 2. The sealing station of claim 1, wherein the sealing tool is configured to apply the sealing force simultaneously onto a packaging tray held in the upper tray holding fixture and a packaging tray held in the lower tray holding fixture.
 3. The sealing station of claim 1, wherein the sealing tool comprises an upper sealing plate and a lower sealing plate.
 4. The sealing station of claim 3, wherein the upper tray holding fixture and the lower sealing plate are movable in a coupled manner.
 5. The sealing station of claim 1 further comprising a controllable force device for applying the sealing force.
 6. The sealing station of claim 1 further comprising a device for registering the sealing force and for regulating the sealing force to a specific value.
 7. The sealing station of claim 1, wherein the sealing tool is configured to evacuate the packaging tray and/or to treat the packaging tray with gas.
 8. The sealing station of claim 1, wherein the upper and the lower tray holding fixtures can be moved by means of a lifting unit.
 9. The sealing station of claim 1 further comprising a gripper system for loading and/or unloading the packaging tray into and/or out of one of the upper and lower tray holding fixtures.
 10. The sealing station of claim 1, wherein the sealing station is configured for incorporation with a packaging machine.
 11. A method for operating a sealing station, comprising the step of simultaneously applying a sealing force to at least one packaging tray located in an upper tray holding fixture and at least one packaging tray located in a lower tray holding fixture.
 12. The method of claim 11, wherein a sealing tool is fed packaging trays in a second level after a first level of the sealing tool has received packaging trays.
 13. The method of claim 12, wherein the first and the second levels of the sealing tool are individually evacuated and/or treated with gas. 